Our invention relates to an apparatus for the recording and/or reproduction of information, particularly digitized information, on magnetic tape packaged in cassette form. More specifically, our invention pertains to a control system in such magnetic tape cassette apparatus for automating its operation associated with the loading and ejection of the tape cassette into and out of the apparatus.
Still more specifically, our invention deals with improvements in or relating to magnetic tape cassette apparatus of the kind described and claimed in U.S. Pat. Appl. Ser. No. 514,515 filed Apr. 25, 1990, now U.S. Pat. No. 5,084,792, by Watanabe and assigned to the assignee of the instant application. The contents of that prior application will be incorporated herein insofar as is necessary for the full understanding of our present invention.
Generally, in digital magnetic tape cassette apparatus, it is essential that the tape cassette on being loaded in the apparatus be precisely positioned with respect to the transducer for proper data transfer therewith. Some prior art devices have had difficulties in meeting this requirement. The difficulties have arisen in such known devices because not only the tape cassette but also the transducer has had to move relative to some stationary part, such as the casing, of the apparatus for the establishment of data transfer contact therebetween. The tape cassette on being inserted in the entrance slot of the apparatus has been first moved to the data transfer position. Then the transducer has been moved into engagement with the tape of the tape cassette.
U.S. Pat. No. 4,701,817 to Uemura, assigned to the assignee of the instant application, represents a conventional approach to the problem discussed above. This patent has made unnecessary the travel of the transducer to and away from the data transfer position; only the tape cassette, on being inserted fully in the entrance slot, travels linearly and in its own plane to the data transfer position opposite the transducer. Then the pair of motor driven spindles, forming parts of a tape transport, are thrust into driving engagement with the hubs of the tape cassette for tape transportation therebetween.
Although this prior art apparatus was well calculated for the establishment of proper positional relationship between transducer and tape cassette, it still had some shortcomings. The tape cassette on full insertion in the entrance slot was sprung into data transfer contact with the transducer. The drive spindles were also sprung into driving engagement with the tape cassette. For ejection, too, purely mechanical means were employed for retracting the drive spindles out of driving engagement with the tape cassette and for subsequently ejecting the tape cassette from the apparatus. The prior art apparatus was therefore very complex in mechanical construction. Also, because of the use of many springs, the operator had to exert a considerable manual force in depressing a push button for the ejection of the tape cassette.
A partial solution to such shortcomings of the Uemura patent is found in the above cross referenced U.S. Pat. Appl. Ser. No. 514,515 filed by Watanabe. The Watanabe application proposed the use of an electric motor in combination with a cam mechanism for moving the drive spindles into and out of driving engagement with the tape cassette. Although the motor driven tape transport shift mechanism according to Watanabe succeeded in drastically reducing the weaknesses of the Uemura patent, it proved to need further refinement for the establishment of true practical utility in the operation of the apparatus of this kind, particularly with regard to the automation of operations associated with the loading and ejection of the tape cassette.
We have found an additional problem left unsolved in the art. That problem arose in use of the head cleaning cassette described and claimed in U.S. Pat. No. 4,748,526 to Miyao et al., also assigned to the assignee of the present application. Shaped and sized like the tape cassette, the cleaning cassette is to be loaded in the apparatus in manually cleaning the head with a cleaning stick. When the cleaning cassette was loaded in the apparatus, the pair of drive spindles were free to rotate in frictional contact with the bottom of the cleaning cassette. Such rotation of the drive spindles is objectionable because of the unavoidable abrasion of the drive spindles as well as of the cleaning cassette.